Question

So… I want to create simple HTTP Chunked transfer encoding prototype. I have messages as std::strings. And my server API is all string based… so I wonder how to turn std::string length into hex and than back into string?

So say we had std::string("This is the data in the first chunk\r\n").length() that would return say int 37. I want to convert it into hex 0x25 and than to get out from that hex std::string("25"). How to do such thing (using stl and boost)?

Answer 1

#include <sstream>
#include <iomanip>
#include <iostream>

int main() {
    // To string:

    std::ostringstream oss;
    oss << std::hex << 37;
    std::string result = oss.str();

    std::cout << result << '\n';

    // Back from string (if you need it):

    std::istringstream iss(result);
    int original;
    if (!(iss >> std::hex >> original)) {
        // handle error here
    } else {
        std::cout << original << '\n';
    }
}